A single Dose of Pegylated Filgrastim (SD/01) is as effective as Daily Filgrastim for Hematologic Support of Chemotherapy in Breast Cancer Patients: Results of a Randomized,k Double-Blind, Phase 3 Trial

Diana Stripp, MD

University of Pennsylvania Cancer
Last Modified: May 12, 2001

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Presenter: F.A. HolmesAffiliation: US Oncology, Houston, TX

Background:

Neutropenia is a frequent result of cytotoxic chemotherapy and increases patient risk for serious infection and treatment failure due to dose-reduction or delay.

Pegylated Filgrastim (long acting, once per cycle) single dose SD/01 has been shown previously to stimulated neutrophil production in a dose-dependent manner.

Cytokines were started 24 hrs post- chemotherapy and continued as daily injections of Filgrastim or placebo until ANC 10x109/L or a total of 14 days.

The primary end point was the duration of severe neutropenia (DSN, days with ANC <0.5x109/L) in cycle 1 chemotherapy, with SD/01 being non-inferior to Filgrastim if the difference in mean DSN was < 1day.

Results:

Baseline demographics were balanced between treatment groups. Approx. 90% of pts were chemotherapy-naïve in both groups, with compararble numbers of stage II to IV pts.

The primary analysis revealed a mean DSN of 1.7 days in the SD/01 arm (n=131) vs. 1.6 days in the Filgrastim arm (n=129).

The incidence of severe neutropenia in cycle 1 was 76% in both groups, with comparable ANC nadirs.

Overall incidence of febrile neutropenia (fever 38.2°C with ANC <0.5x109/L) was 9% in the SD/01 arm and 18% in Filgrastim arm.

There was no difference in the nadir ANC between the 2 groups after cycle 1. However, the mean nadir ANC were higher in the SD/01 groups after the subsequent cycles.

No differences were noted in safety measures, including duratin or intensity of bone, joint or muscular pain; or headache.

Authors' Conclusions

SD/01 is comparable to Filgrastim in reducing the DSN (associated with the incidence of febrile neutropenia) following myelosuppressive chemotherapy.

These results are very similar to a European study presented at ASCO this year (Abstract 90), which helps to confirm the efficacy and safety of Pegylated Filgrastim. Once per chemotherapy cycle administration of Pegylated Filgrastim appears to be safe and effective, and will be more convenient to patients.